Mycobacteriosis among northern snakehead fish in the Potomac River
Mycobacteriosis among northern snakehead fish in the Potomac River
Piscine mycobacteriosis, caused by infection with several species of mycobacteria, is a chronic disease of fishes that occurs worldwide. Effects on fishes range from the subclinical to fulminant epizootics with concurrent mortality. Some species of Mycobacteria that infect fishes also have zoonotic potential and associated human health implications. Mycobacteriosis has been reported among cultured snakehead species in Asia, and in 2014, it was identified in a northern snakehead collected from Pohick Bay in the Potomac River system. In 2015 and 2017, northern snakehead fish collected from Potomac River tributaries were screened for health parameters, including the presence of mycobacteriosis. None of the fish collected displayed gross external or internal evidence of disease associated with mycobacteriosis. A subset of the health-screened snakehead was assessed for the presence of Mycobacterium sp. and associated lesions through histopathological analysis and Mycobacterium-specific microbial culture methodology. In 2015 and 2017, approximately 60% of these northern snakehead examined had chronic granulomatous inflammation within internal organs (predominantly kidney or spleen) consistent with chronic mycobacterial associated lesions. Presumptive Mycobacterium sp. (acid fast-positive organisms grown on media selective for Mycobacterium) were recovered from kidney/spleen tissues from approximately 33% of northern snakehead collected and analyzed in 2015 and 2017. Nucleic acid sequence analysis to determine species of the Mycobacterium isolates is underway. Further investigation into northern snakehead mycobacteriosis in the Potomac River system and throughout the region will help to determine the prevalence and potential impacts of the disease among these fish and other aquatic wildlife.
References:
Densmore, C.L., Iwanowicz, L.R., Henderson, A.P., Iwanowicz, D.D., & Odenkirk, J.S. (2016). Mycobacterial infection in Northern snakehead (Channa argus) from the Potomac River catchment. Journal of fish diseases, 39 6, 771-775.
Mycobacteriosis among northern snakehead fish in the Potomac River
Piscine mycobacteriosis, caused by infection with several species of mycobacteria, is a chronic disease of fishes that occurs worldwide. Effects on fishes range from the subclinical to fulminant epizootics with concurrent mortality. Some species of Mycobacteria that infect fishes also have zoonotic potential and associated human health implications. Mycobacteriosis has been reported among cultured snakehead species in Asia, and in 2014, it was identified in a northern snakehead collected from Pohick Bay in the Potomac River system. In 2015 and 2017, northern snakehead fish collected from Potomac River tributaries were screened for health parameters, including the presence of mycobacteriosis. None of the fish collected displayed gross external or internal evidence of disease associated with mycobacteriosis. A subset of the health-screened snakehead was assessed for the presence of Mycobacterium sp. and associated lesions through histopathological analysis and Mycobacterium-specific microbial culture methodology. In 2015 and 2017, approximately 60% of these northern snakehead examined had chronic granulomatous inflammation within internal organs (predominantly kidney or spleen) consistent with chronic mycobacterial associated lesions. Presumptive Mycobacterium sp. (acid fast-positive organisms grown on media selective for Mycobacterium) were recovered from kidney/spleen tissues from approximately 33% of northern snakehead collected and analyzed in 2015 and 2017. Nucleic acid sequence analysis to determine species of the Mycobacterium isolates is underway. Further investigation into northern snakehead mycobacteriosis in the Potomac River system and throughout the region will help to determine the prevalence and potential impacts of the disease among these fish and other aquatic wildlife.
References:
Densmore, C.L., Iwanowicz, L.R., Henderson, A.P., Iwanowicz, D.D., & Odenkirk, J.S. (2016). Mycobacterial infection in Northern snakehead (Channa argus) from the Potomac River catchment. Journal of fish diseases, 39 6, 771-775.